It is proposed here to carry out a detailed theoretical study of the dynamics of the conformational changes of retinal in the first steps of the vision process. The recent experimental information from picosecond laser experiments and from resonance Raman spectroscopy indicates that the first step in the vision process is faster than 6 picoseconds and that the detailed binding of the retinal inside the protein, changes significantly in this step. Here we propose to interpret this experimental information, as well as other types of experimental information, and to analyse the dynamical nature and the conformational changes in the bleaching process. We intend to use two powerful theoretical methods in this study: the resonance Raman spectra will be interpreted by our recent method for complete evaluation of vibronic transition intensities (this is at present the only theoretical method capable of calculating the detailed resonance Raman spectrum of large molecules). The dynamical nature of the bleaching will be studied by our recent semiclassical trajectory approach which allows one to study the dynamics of cis-trans photoisomerization of large molecules as a function of time, with the variation of all molecular degrees of freedom. In the first stage of the proposed research we will study the photoisomerization reaction of stilbene and retinal by the semiclassical trajectory approach; we will attempt to calculate the quantum yield, and the relaxation life time and their dependence on the excitation energy. In the second stage, we will study the resonance Raman spectra of differently substituted retinals in solution and in the crystalline state, trying to examine (and if needed to recalibrate) our theoretical approach. In the final step we will apply both types of calculations to retinal inside different models of active sites. We hope that the reproduction of the resonance Raman and picosecond experiments by such model calculations will provide a unique interpretation for the details of one of the more important primary biological processes.